M-like protein SrM is not crucial to the virulence of a novel isolate of Streptococcus equi subsp. ruminatorum from Macaca mulatta.

In this study, a Streptococcus strainnamed FJ1804, was isolated from a blood sample collected from a dead Macaca mulatta in China and, was subsequently classified as Streptococcus equi subsp. ruminatorum (S.e. ruminatorum) through 16S rRNA gene sequence analysis. After whole genome sequencing and analysis, an M-like protein encoding gene that encodes an SrM protein that is homologous to the crucial S.e. zooepidemicus crucial virulence factor SzP, was identified in the genome of FJ1804. To determinethe function of SrM in this bacterium, a strain deleted of srm as well as a complement strain were constructed. The results of in vitro cell adherence, invasion and phagocytosis assays and in vivo animal challenge and histopathology showed that the anti-phagocytosis was decreased and the adherence rate was increased in the srm deletion strain, whereas the invasion rate, pathological features and LD50 values inboth zebrafish and BALB/c mice model showed no difference compared to that observed for the WT strain. To the best of our knowledge, this is first of an infection caused by S.e. ruminatorum, which is a newly identified zoonotic pathogen, in Macaca mulatta, and our data suggest that, compared with other S.e. zooepidemicus strains, the SzP homologous protein is not crucial to the virulence of this bacterium.

[Multi-center study of premature thelarche and gynecomastia in Chinese infants and toddlers].

OBJECTIVE: The term "premature thelarche" refers to isolated breast development before 8 years of age in female, without any other signs of sexual maturation, while "gynecomastia" is the presence of breast tissue in males. This study aimed to investigate the prevalence of premature thelarche and gynecomastia in Chinese infants and toddlers, identify the potential risk factors, and explore the influence of early breast development on physical growth, mental development and psychomotor development. METHOD: A total of 1 510 full term and healthy children at the age of 0-48 months were sampled by stratified cluster random sampling method from 8 provinces from 2011-2012. Weight, height and breast development were assessed by senior primary pediatricians, while Bayley Scale of Infant Development-I (BSID-I) was used to measure the mental developmental index (MDI) and psychomotor developmental index (PDI) for children aged 2-30 months. Social-demographic Questionnaires were completed by the caregivers. RESULT: The combined prevalence of premature thelarche and gynecomastia was 1.6% (23/1 475), girls 2.2% (15/695), boys 1.0% (8/780), all within 2 years of age. The birth weight, feeding patterns in first 4 months, delivery mode, weaning time and social economic status were not significantly associated with the breast development. However, lower father's education level (OR = 3.632, 95%CI = 1.565-8.432) as well as smoking mother (OR = 18.960, 95%CI = 1.590-226.304) were significantly related to breast development even after adjusting for potential confounders. Lower weight (-0.479 ± 0.648 vs. 0.005 ± 0.987, P < 0.05) and height (-0.602 ± 1.042 vs. 0.008 ± 0.986, P < 0.05) Z score were found in breast development group, even after adjusting for age, gender and father' education level. Neither mental development (t = -0.082, P > 0.05) nor psychomotor development (t = 1.054, P > 0.05) was associated with breast development. CONCLUSION: We showed a similar prevalence of premature thelarche with the data reported in similar studies reported from other countries. Among the 0-48 months old infants and toddlers, Father's education level and smoking mother were both related to breast development. Breast development was significantly associated with physical growth, but had no correlation with the mental or psychomotor development.